[SCSI] be2iscsi: Adding a shutdown Routine

This patch adds a shutdown routine. It fixes a bug where when be2net
and be2iscsi are both used be2iscsi was not cleaning up its resources
properly causing be2net to fail to get loaded when the system is
rebooted.

Signed-off-by: Jayamohan Kallickal <jayamohan.kallickal@emulex.com>
Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>